title: p38 mitogen-activated protein kinase regulates canonical Wnt-beta-catenin signaling by inactivation of GSK3beta.
abstract: The Wnt-beta-catenin canonical signaling pathway is crucial for normal embryonic development, and aberrant expression of components of this pathway results in oncogenesis. Upon scanning for the mitogen-activated protein kinase (MAPK) pathways that might intersect with the canonical Wnt-beta-catenin signaling pathway in response to Wnt3a, we observed a strong activation of p38 MAPK in mouse F9 teratocarcinoma cells. Wnt3a-induced p38 MAPK activation was sensitive to siRNAs against Galpha(q) or Galpha(s), but not against either Galpha(o) or Galpha(11). Activation of p38 MAPK is critical for canonical Wnt-beta-catenin signaling. Chemical inhibitors of p38 MAPK (SB203580 or SB239063) and expression of a dominant negative-version of p38 MAPK attenuate Wnt3a-induced accumulation of beta-catenin, Lef/Tcf-sensitive gene activation, and primitive endoderm formation. Furthermore, epistasis experiments pinpoint p38 MAPK as operating downstream of Dishevelleds. We also demonstrate that chemical inhibition of p38 MAPK restores Wnt3a-attenuated GSK3beta kinase activity. We demonstrate the involvement of G-proteins and Dishevelleds in Wnt3a-induced p38 MAPK activation, highlighting a critical role for p38 MAPK in canonical Wnt-beta-catenin signaling.
authors.affiliation: Department of Pharmacology, Health Sciences Center, State University of New York at Stony Brook, Stony Brook, NY 11794-8651, USA. kamesh@pharm.stonybrook.edu
authors.forename: Rama Kamesh
authors.initials: RK
authors.lastname: Bikkavilli
authors.forename: Michael E
authors.initials: ME
authors.lastname: Feigin
authors.forename: Craig C
authors.initials: CC
authors.lastname: Malbon
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism; D000818:Animals; D045744:Cell Line, Tumor; D000072261:Dishevelled Proteins; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D019204:GTP-Binding Proteins / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic; D038362:Glycogen Synthase Kinase 3 / Q000378:metabolism*; D000071679:Glycogen Synthase Kinase 3 beta; D006801:Humans; D051379:Mice; D008954:Models, Biological; D010750:Phosphoproteins / Q000378:metabolism; D051153:Wnt Proteins / Q000378:metabolism*; D051176:beta Catenin / Q000378:metabolism*; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D000072261:Dishevelled Proteins; D004791:Enzyme Inhibitors; D010750:Phosphoproteins; D051153:Wnt Proteins; D051176:beta Catenin; C000605506:GSK3B protein, human; D000071679:Glycogen Synthase Kinase 3 beta; C000605507:Gsk3b protein, mouse; D048051:p38 Mitogen-Activated Protein Kinases; D038362:Glycogen Synthase Kinase 3; D019204:GTP-Binding Proteins